1. Technical Field
The present invention relates to a facsimile device capable of printing received images on both sides of a recording sheet.
2. Related Art
Conventionally, there has been known a double-surface printing type facsimile device which is capable of printing received image of an original on both sides of a recording sheet. An example of such a technology is disclosed in Japanese Patent Provisional Publication No. P2004-104264A (hereinafter, referred to as '264 publication).
FIG. 8 schematically shows a configuration of the double-surface printing facsimile device similar to one disclosed in '264 publication.
As shown in FIG. 8, the double-surface printing facsimile device includes, along a sheet feed path 110, a pair of feed rollers 107, a registration sensor 108, a pair of registration rollers 104, a photosensitive roller 103, a transfer roller 105 and a pair of fixing rollers 102. The sheet feed path 110 is connected with a reverse feed path 111. At a diverging point between the sheet feed path 110 and the reverse feed path 111, a diverging sensor 106 is arranged. Along the reverse feed path 111, on the downstream side of the diverging sensor 106, a pair of reverse rotation rollers 109 and a discharge sensor 101 are arranged. The feed rollers 107 and the reverse rotation rollers 109 are driven to rotate by a stepping motor 115.
With the above configuration, the double-surface printing is performed as described below.
Firstly, from a sheet feed cassette (not shown), one of recording sheets is picked up and fed toward the pair of feed rollers 107. During the feeding of the recording sheet, along the sheet feed path 110, toward the registration rollers 104, the leading edge of the recording sheet is detected using the registration sensor 108. In response to detection of the leading end of the recording sheet by the registration sensor 108, rotation of the registration rollers 104 is stopped so that the leading end of the recording sheet abuts the registration rollers 104 and its orientation is corrected (i.e., skew, or the inclination of the recording sheet with respect to the sheet feed direction is corrected).
Thereafter, rotation of the registration rollers 104 are restarted and the recording sheet is fed toward a nip between the photosensitive roller 103 and the transfer roller 105. At the nip therebetween, the image is transferred from the photosensitive roller 103 onto the recording sheet, and then the transferred image is fixed on the recording sheet with heat and pressure applied by the fixing rollers 102.
The recording sheet is then fed from the sheet feed path 110 to the reverse feed path 111. When the diverging sensor 106 detects the leading edge of the recording sheet, the reverse rotation rollers 109 are rotated so that the recording sheet is fed toward the discharge sensor 101.
When the recording sheet is fed in the reverse feed path 111, the front and back surfaces of the recording sheet are reversed with respect to a state when the recording sheet was picked up from the sheet feed tray.
When the discharge sensor 101 detects the recording sheet, the reverse rotation rollers 109 are reversely rotated so that the recording sheet is fed in a direction away from the discharge sensor 101. The recording sheet as reversed is fed from the reverse rotation rollers 109 toward the sheet feed rollers 107 (i.e., the recording sheet is fed from the reverse feed path 111 to the sheet feed path 110). As described above, at this stage the front and back surfaces of the recording sheet have been reversed.
As the recording sheet is fed toward the nip between the photosensitive roller 103 and the transfer roller 105, the surface bearing the previously transferred image faces the transfer roller 105, and a surface on which no image has been printed faces the photosensitive roller 103. Then, an image is transferred from the photosensitive roller 103 to the recording sheet, and fixed by the fixing rollers 102, thereby the double-surface printing has been completed. The recording sheet to which the double-surface printing has been applied is then fed toward the discharge sensor 101, and at this time, discharged onto the discharge tray 112.
If the double-surface printing facsimile device is configured to discharge the recording sheet with its back surface oriented upward (hereinafter, referred to as face-down state), an image of an even number page is printed firstly on one surface of the recording sheet, and then an image of an odd number page is printed on the other surface of the recording sheet.
Typically, such a double-surface printing type facsimile device is capable of printing images on both sides of the recording sheet as it receives facsimile data, or storing the received facsimile data in a storage, and then printing images based on the stored facsimile data. Specifically, the double-surface printing type facsimile device may be configured such that the image data for a first page is stored in a storage (e.g., a page memory) as the image data is received without printing the same on the recording sheet. Then, the facsimile device receives the image data for a second page, which is also stored in a storage (e.g., the page memory).
When the image data for both the first and second pages of the recording sheet is accumulated (stored) in the storage, images corresponding to the stored image data for the first and second pages are printed in a double-surface printing mode on both sides of the recording sheet, respectively. Thereafter, the facsimile device operates such that printing is not executed when an image of an odd number page is received, and after an image of an even number page has been subsequently received, both images of the odd and subsequent even number pages are printed on the both surfaces of the recording sheet in the double-surface printing mode. It should be noted that when the last page of a transmitted document is an odd number page, the image of the last page is printed in the single-surface printing mode.
Incidentally, the facsimile data is created by a transmission source side, and it cannot be recreated at a transmission received side. Therefore, according to '264 publication, the received document (facsimile data) is stored for backup. If wrong recording sheets (e.g., recording sheets one side surface thereof already bearing some image: which will be referred to as a used recording sheet hereinafter) are set to the facsimile device and the double-surface printing is performed, the received image overlaps the printed image on the used recording sheet. Even in such case, if the back up data is stored, the received document can be re-printed on the correct recording sheets.
In '264 publication, in order to avoid a storage for storing the received facsimile data form being filled with backup data, a user is allowed to selectively delete images and/or the oldest backup data is automatically deleted.
According to '264 publication, however, since all the received image data is stored for backup, the storage is required to have a sufficient capacity, which causes increase of manufacturing cost. Although the facsimile device according to '264 publication is configured that the user can selectively delete the stored images, the capacity should be considerably large since the received data must be stored even if the user forget to delete the images.
Further, according to '264 publication, the oldest data is automatically deleted to save the capacity of the storage. However, according to such a configuration, since the image data which has been appropriately printed is still stored, the storage is not efficiently used.